Typically, after the install, AMP will take roughly 5-10 minutes to start up. A way to check is to watch the processes using the following commands:
# daemons
--> this lists out the running daemons at the moment the command is given
# wd
(this is an alias for # watch daemons)
--> this is same as above but refreshes every second
Once this list is populated to about 15 daemons, the AMP UI should be available. If it's taking longer than 5-10 minutes, it could mean that you're hitting a potential performance issue (if that's the case, check "# top -c", make sure swap isn't being hit).